Dust cover for automatic telephone switch mechanism



April 1961 E. J. BENlSEK 2,978,137

DUST COVER FOR AUTOMATIC TELEPHONE SWITCH MECHANISM Filed Oct. 2, 1957INVENTOR. EDWARD J. BENISEK ATTY.

Unitid ai aren 'DUST COVER FOR AUTOMATIC TELEPHONE SWITCH MECHANISMEdward J. Benisek, Geneva, 11]., assignor to Automatic ElectricLaboratories, Inc., a corporation of Delaware Filed Oct. 2,1957 Ser- No.687,664

' 4 Claims. (Cl. 220-18 My inventionrelates in general to covers, andmore specifically to an improved dust cover for an electrical switchingmechanism such as an automatic Patented Apr. 4, 1961 tain mounting holesand screws on the back of plate 1.

This box 6 is secured to the back of back plate 1 by means of a mountingscrew or screws (not shown) which pass through holes in box 6 and intothreaded holes in plate 1. One such screw is shown in the prior 687,388,previously mentioned.

A horizontal shelf 7 is'mounted in the usual manner to the lower frontside of plate 1 and extends forward at right angles thereto. Shelf 7 isslightly wider than plate 1, and also extends forward to form a base onwhich the cover rests as will be explained.

telephone means for moving theshaft in a vertical and rotary mo- 7 tionto cause the wipers to connect with a set ofcontacts in said bank. Thereare also certain relays sets knownas repeaters and other relay setsandsuch s witches' or relay switching mechanisms are usually mounted on arectangularly shaped vertical plate having a horizontal shelf at itslower end extending forwardly from its lower edge. The vertical plateusually has backwardly turned sides with bayonet slots therein formounting the whole assembly on a rack or shelf having pins cooperatingwith said slots.

In the past the covers for enclosing and dust proofing such devices wereusually also provided with extending sides having bayonet slots whichhooked over the same pins which supported the switch mechanism on therack. Due to the closeness of the switches when mounted on the rack sucha mounting of the covers sometimes caused a binding of the edges of thecovers of two adjacently mounted switches.

One attempt to overcome this difliculty is shown in the priorapplication of Bjorn Smith, Serial No. 687,388 filed October 1, 1957, onwhich my invention is in the nature of an improvement.

The switch cover as described in said prior application, basicallyincludes a sheet of metal, such as thin steel plate, bent around in a Ushape with a circular front and parallelly extending sides, togetherwith a top plate with its outer edges also of U shape and with its edgesturned down over the steel plate and welded thereto as shown. The backand bottom sides of the cover are open.

The object of my improved design is therefore to provide improvedlatching means for securing the cover to the vertical plate andhorizontal shelf of the switch mechanism without any binding of theparts.

Referring to the accompanying sheet of drawings I will now describe thedetailed construction of the cover.

Fig. 1 is a side view of my improved cover shown in mounted position onthe v vertical plate and shelf of a switching mechanism.

Fig. 2 is a view taken from the top of Fig. 1.

Fig. 3 is a partial view taken from the right side of Fig. 1 showing thetop latching means.

Fig. 4 is a partial view taken .in an upward direction from the lowercorner of Fig. 1 as indicated by the line 4-4 of Fig. 1.

In the drawing I have shown the usual vertical back mounting plate 1having its two sides turned back to form mountings flanges 2. and 3 eachhaving a pair of bayonet slots such as 4 and 5 by means of which theswitch mechanism is hung or mounted on pins 18 of the usual mountingrack or shelf. There is a metal box or cover 6 secured to the u er rearside of plate 1 which covers cer- The cover is formed of two majorparts, the front and sides are formed from a single thin sheet of metal8, of steel or the like which is formed in a U shape with a semicircularfront and parallel sides extending backward therefrom. The top plate 9is also of thin sheet metal with its front section curved to correspondto the front of plate 8 and with its front and side edges turned downaround and welded to the upper edge of plate 8 to hold the same in itsproper shape; Small embossed portions such as 8a are'punched out fromthe upper edges of plate 8 to form locating points against which theturned down edges of plate 9 abut, to center the top plate in welding.The plate 8 has a pair of reinforcing ribs 11 and 12 indented thereinand a vertical reinforcing rib formed therein at 13. Another reinforcingelement is the sheet of metal 14 which is folded over the lower edge andwelded thereto.

The rear edge of top plate 9 is extended beyond the turned down edgeswhich are welded to plate 8 and is curved downward across its free endto form a latching lip 16. This lip 16 is curved downward in asemicircle to conform to and fit snugly over the upper ends of mountingflanges 2 and 3. The ends of lip 16 which extend down over flanges 2 and3 are tapered or thinned down, as indicated in Fig. 1. Two reinforcingribs 16a and 16b provide the necessary rigidity to lip 16 so that as ithooks over the ends of 2 and 3 the top of the cover will be held tightlyin place.

At the lower front edges of the parallel sides of plate 8 are a pair of.downwardly extending prongs or extensions 17 one of which is shown inFigs. 1 and 4. Each prong has a cam surface 17a which extends over andslides down behind the rear projecting end of horizontal plate 7. Aspreviously stated, this plate 7 is slightly wider than the back plate 1.

When the cover is applied to the frame of the switch mechanism, it ispushed inward in a slightly elevated position until the rear edges 19engage the pins 18 and lip 16 falls over the upper ends of flanges 2 and3 and until the prongs 17 pass down behind the rear edges of plate 7.The cover is then pushed downward to the position shown in Fig. 1 andheld securely in position against the pins 18 by lip 16 at the top andthe prongs or extensions 17.

Having fully described the features and aspects of my invention, what Iconsider to be new and desire to have protected by Letters Patent willbe pointed out in the appended claims.

. What I claim is:

1. The combination with a vertical back plate having a pair of verticalmounting flanges extending backward from the sides thereof with roundedupper ends and having a shelf comprising a horizontal base plate at thelower edge thereof having a semicircular front edge and having backedges extending outward beyond the back plate, of a cover comprisingfront and side walls and a top plate forming a cover with open back andbottom and with sides conforming to the shape of the back plate andshelf, said top plate having an extending lip curved over to fit saidrounded 'upper ends of said flanges, and

application, S.N.

the side walls of said cover having extensions at the lower back edgesthereof fitting over the outwardly extending back edges of said shelf,said extending lip engaging said rounded upper ends, and said extensionsengaging said outwardly extending back edges of said shelf to form thesole means for holding the cover removably in place, when the cover isplaced on the back plate, and said cover requiring only a verticalmovement thereof to remove it from the back plate.

2. The combination of cover formed from a piece of sheet metal curvedinto a U shape with semicircular front and parallel sides, a flat topwith a curved front with the edges of its front and sides turned downand rigidly secured to the top of said sheet metal piece, a pair ofbosses in the upper rear ends of said sides forming points of alignmentby butting against the ends of the turned down sides of said flat top toproperly position the top on said front and sides of the piece of sheetmetal, With a vertical back plate having a' forwardly extending baseplate at its bottom edge, with its side edges extending outward beyondthe sides of said back plate, said back plate also having a pair ofvertical mounting flanges extending backward from the sides thereof andhaving rounded upper ends, a curved lip formed on the rear of said topof the cover engaging the said rounded upper ends of said mountingflanges, a pair of downwardly ex tending flanges, one on each of thelower rear edges of said cover sides engaging the extending side edgesof said base plate, said lip and said flanges effective to secure 4 thecover in place on said back plate, said cover thereby removable from theback and base plates by a single vertical movement.

3. A combination such as claimed in claim 2 in which the curved lipformed on the top of the cover has the turned down edge thereof taperedin thickness so that the portion extending down over the top of the saidrounded upper ends of the mounting flanges is thinner than the upperportion thereof, and a pair of stiffening ribs in said top adjacent saidlip to reenforce the same.

4. A combination such as claimed in claim 2, in which there is avertical stiffening rib extending along each rear edgeof the parallelsides of the cover, said ribs extending down into the extending flangesto stilien the same.

References Cited in the file of this patent UNITED STATES PATENTS111,225 McCallum Ian. 24, 1871 556,612 Bingaman Mar. 17, 1896 1,065,875Keagy et a1. .4 June 24, 1913 1,156,974 Chapman Oct. 19, 1915' 1,379,228Swift May' 24, 1921 1,408,370 Lincoln Feb. 28, 1922 1,6 201'047 VanValkenburg Mar. 8, 1927 2,184,047 King Dec. 19, 1939 2,497,561 Rose Feb.14, 1950 2,521,134 Staniti Sept. 5, 1950 2,737,754 Goss' Mar. 13, 1956

